The present invention relates to a novel triboluminescent inorganic material capable of emitting strong luminescence under a mechanical force such as frictional rubbing, impacting and the like or under a mechanical stress as well as to an efficient method for the preparation of such a triboluminescent inorganic material.
As is known, various kinds of inorganic luminescent materials are known and widely employed in practical applications. These conventional inorganic luminescent materials heretofore developed are grossly classified into, first, those emitting luminescence by receiving an electric energy as in the excitation in an electric field or under irradiation with electron beams and, second, those emitting luminescence when irradiated with light of various wavelengths such as ultraviolet and infrared lights and ionizing radiations.
On the other hand, certain inorganic materials known as a triboluminescent material are capable of emitting luminescence by receiving mechanical energy. While several natural materials such as certain kinds of wurtzite minerals are known to be triboluminescent, the intensity of their triboluminescence is so low that no practical application is undertaken and no reports were published heretofore on the research and development works of synthetic inorganic triboluminescent materials which can be used either in the form of a powder or block or in the form of a thin film formed on a substrate. Accordingly, there is a motivation to conduct investigations for the development of a synthetic inorganic triboluminescent material capable of emitting practically usable strong luminescence by excitation with mechanical energy.